1. Field of the Invention
The present invention relates to a pointing device that can be operated to move an operational object on a display screen in any direction and at any speed, its control method and as a mobile telephone provided with such pointing device.
2. Description of the Related Art
A mobile telephone is provided with operating buttons for inputting numerals or characters and operating buttons, a jog dial, and the like, for moving a cursor, a pointer or a selection frame displayed on a display screen of the mobile telephone.
FIGS. 12a and 12b are front elevational views of typical mobile telephones.
Operating buttons 51 for moving a cursor, a pointer or a selection frame displayed on a display screen 52 of a mobile telephone 1 may take various forms. The operating buttons, in any form, are provided with four on-off operating mechanical switches (not shown) thereunder, which correspond to the up-and-down and the left-and-right directions on the display screen 52, for moving an operational object such as the cursor, the pointer or the selection frame on the display screen 52 in the up-and-down and left-and-right directions.
For example, as shown in FIG. 12a, mechanical switches (not shown) may be provided just under each of four independent operating buttons 51a, 51b, 51c and 51d in the up-and-down and the left-and-right positions. Alternatively, in another example shown in FIG. 12b, there is provided one operating button 51, on the surface of which marks 53a, 53b, 53c and 53d are printed for indicating the up-and-down and left-and-right directions and, then, mechanical switches (not shown) are disposed just under each of the marks 53a, 53b, 53c and 53d. 
In each case, when a user pushes down a desired position of the operating buttons 51, 51a, 51b, 51c and 51d, only one mechanical switch disposed just under the pushed position among the four mechanical switches turned on to output a specific signal. Therefore, according to the above configuration, when the operation buttons 51, 51a, 51b, 51c and 51d are operated, the operational object such as the cursor, the pointer or the selection frame can be moved only in either one of up, down, left and right directions.
FIGS. 13a and 13b are diagrams illustrating menu representations displayed on the display screen of the mobile telephone.
The mobile telephone not only functions as a telephone but also has various features and usages (applications) available to the user such as an internet connection function, an e-mail function, games, a mobile telephone ringing tone setting, an incoming and outgoing call history, a telephone directory memory and so on. The menu representations as illustrated in FIGS. 13a and 13b are typically provided for allowing the user to select such features and usages of the mobile telephone easily. The user refers to the menu representation on the display screen 52 and manipulates the operating buttons (not shown) to move the selection frame (indicated as frames enclosed in double lines in FIGS. 13a and 13b and thereafter) to the position of an icon 54 indicating the feature or usage the user desires.
For example, in the example shown in FIG. 13a, on the display screen 52, the icons 54 for indicating the features and usages that the user can select are disposed in the vertical direction. Alternatively, in the example shown in FIG. 13b, the icons 54 are disposed in eight directions including up, down, left and right. Besides these examples, though not shown here, the icons may be disposed only in the transverse direction or the icons that cannot be displayed on the display screen at a time may be displayed in a scrolling manner. Generally speaking, the display form of the menu on the display screen of the mobile telephone can be customized into an icon arrangement that the user desires.
On the other hand, a pointing device that can output a signal for moving the operational object such as the cursor, the pointer or the selection frame on the display screen in any direction and at any speed has already been implemented and is often used mainly as a coordinate input device for a computer.
Here, by way of example, the operational principle of a pointing device employing a variation of magnetism will be described briefly.
FIGS. 14 and 15 are principle drawings of the pointing device employing a variation of magnetism.
The pointing device 2 is comprised of a magnet 61 that co-operates with an operating part (not shown) and magnetic reaction elements S1, S2, S3 and S4 for detecting an inclination (in the case of FIG. 14) or a movement (in the case of FIG. 15) of the magnet 61.
The magnetic reaction elements S1, S2, S3 and S4 convert a magnetic field into a voltage to be output and are disposed symmetrically with regard to a predetermined reference point on a substrate 62. For example, the magnetic conversion elements S1 and S2 may be disposed in the X direction and the magnetic conversion elements S3 and S4 may be disposed in the Y direction, respectively.
The magnet 61 has a cylindrical configuration and forms the magnetic field in the vertical direction with regard to its bottom surface. The magnet 61 is disposed above the substrate 62 so that the line normal to the center of the bottom surface of the magnet 61 passes through the substrate 62 vertically at the reference point mentioned above.
When the magnet 61 is not operated or, in other words, when the bottom surface of the magnet 61 is maintained in parallel with the substrate 62 (FIG. 14) or when the center of the bottom surface of the magnet 61 is located on the line normal to the reference point described above (FIG. 15), the magnet 61 is spaced substantially equidistantly from each of the magnetic reaction elements S1, S2, S3 and S4. Here, it is to be noted that the position of the magnet 61 at this time is referred to as the return position in this specification. When the magnet 61 is located at the return position, a substantially equal magnetic field is applied to each of the magnetic reaction elements S1, S2, S3 and S4 and, therefore, each magnetic reaction element outputs an equal voltage value.
When the magnet 61 is manipulated so that it is inclined or moved, the magnetic fields applied to the respective magnetic reaction elements S1, S2, S3 and S4 are changed and the voltage value output from the respective magnetic reaction elements are also changed. For example, when the magnet 61 is inclined or moved positively in the X direction, the output voltage of the magnetic reaction element S1 becomes larger than the output voltage of the magnetic reaction element S2.
From such a variation of the output of each of the magnetic reaction elements S1, S2, S3 and S4, a signal that can move the operational object on the display screen in any direction and at any speed can be calculated.
As described above, as the pointing device employing a variation of magnetism has an advantage in that it has good operability and it can be reduced in size and weight relatively easily, it is coming into widespread use not only as the coordinate input device for the computer but also as control command devices for various electrical apparatus such as machine tools, robots, transportation machines, medical equipment, game machines and so on.
As the features of the mobile telephone, such as the internet connection feature and the game feature, become increasingly sophisticated, it is expected that a pointing device that can be operated to move the operational object on the display screen in any direction will be adopted into compact mobile equipment including mobile telephones, in place of the conventional operation buttons of the mechanical switch type.
As described above, in mobile telephones, for example, the icons of the various features and usages that the user can select are displayed as the menu in rows in the vertical and/or horizontal directions on the display screen. Therefore, in the case of such menu representation, the operability may be improved if the operational object such as the cursor, the pointer or the selection frame can be moved only in the vertical or horizontal directions along which the icons are arranged.
As an example of the conventional techniques, as disclosed in Japanese Unexamined Patent Publication No. 10-239762, there has been proposed a machine adopting a joystick that can move a cursor in any direction by manipulating one lever as means for moving the cursor on a display screen when a desired image pattern is selected from a menu representation.
Further, as disclosed in Japanese Unexamined Patent Publication No. 5-181603, there has been proposed a mouse that is operated while pressing down a particular button provided on the mouse when it is desired to move a cursor only in one of the up, down, left and right directions.
Thus, various contrivances have been made for moving the operational object such as the cursor on the display screen efficiently.
It should be avoided to restrict the biggest advantage of the pointing device in that the operational object on the display screen can be operated in any direction and at any speed. Therefore, though the features of the mobile telephone and, in particular, the menu features, may be enhanced for accommodating the pointing device that can be operated in any direction and at any speed, the development of such features may take very much time and effort in this case because an operating system that is commonly used dedicatedly for the mobile telephone at present must be improved fundamentally. Further, from the viewpoint of the user, it may be preferred that the operability of the operation buttons of the mechanical switch type as described above that has been familiar to the user is reserved to some extent.
Therefore, in view of the above problem, it is an object of the present invention to provide a pointing device having improved operability that can be operated to move an operational object on a display screen in any direction, and its control method, as well as a mobile telephone provided with such pointing device.